Good idea!
Recently i saw that someone (cant remember who it was) posted about a new bed she bought for her yorkie that you heat in the microwave and it stays warm for up to 6 hours. I guess her yorkie absolutely loved it!
I believe it is called a snuggle safe pet warming disk, and she bought it at either petsmart or petco. I wrote it down so i would be sure to buy one for my future yorkie.
